Corrosion inhibitors for use in oil and gas wells and similar applications

Abstract

Anti-corrosion additives and processes useful for oil drilling and similar applications. Heteropoly complex anions of transitional metal elements can be added to an oil well drilling solution which includes a metallic salt, optionally in combination with transition metal compounds or compounds of the metallic elements of Groups IIIa to VIa of the Periodic Table of Elements, to minimize corrosion of systems within which the solution is used.

That which is claimed is:  
     
       1. A solution having corrosion inhibiting properties useful in oil and gas well drilling systems, the solution comprising: 
       an aqueous solution comprising at least one zinc halide, at least one alkaline earth metal salt, or a mixture thereof; and  
       at least one heteropoly complex anion of a transition metal element present in an amount sufficient to provide a corrosion inhibiting effect.  
     
     
       2. The solution of  claim 1 , wherein said alkaline earth metal salt comprises one or more calcium halides. 
     
     
       3. The solution of  claim 1 , wherein said solution comprises at least one zinc halide and at least one calcium halide. 
     
     
       4. The solution of  claim 3 , wherein said solution comprises zinc bromide, optionally zinc chloride, calcium bromide, and optionally calcium chloride. 
     
     
       5. The solution of  claim 1 , said solution further comprising at least one additional corrosion inhibiting additive in an amount sufficient to provide a corrosion inhibiting effect. 
     
     
       6. The solution of  claim 1 , wherein said at least one heteropoly complex anion comprises a compound selected from the group consisting of [X a M b O c ] −n , [X a Z d M b O c ] −n , [X a Z d M b O c H e ,] −n , [X a M b O c (OH) f ] −n , [X a Z d M b O c (OH) f ]−n, and mixtures thereof, wherein: 
       X and Z are central heteroatoms selected from the group consisting of elements from Groups I-VIII of the Periodic Table of Elements;  
       a is 1 or 2;  
       d is an integer from 0 to 4;  
       M b O c , M b O c H e , and M b O c (OH) f  are oxoanions in which M is a transition metal element; b is an integer from 5 to 22; c is an integer from 20 to 70; e is an integer from 0 to 6; and f is an integer from 0 to 3; and  
       n is the charge of the anion.  
     
     
       7. The solution of  claim 6 , wherein: 
       X is phosphorus, silicon, manganese, tellurium or arsenic; and  
       M is molybdenum or tungsten.  
     
     
       8. The solution of  claim 1 , wherein said at least one heteropoly complex anion is selected from the group consisting of phosphomolybdates, silicon molybdates, manganese molybdates, silicon tungstates, tellurium molybdates, arsenic molybdates, and mixtures thereof. 
     
     
       9. The solution of  claim 1 , wherein said at least one heteropoly complex anion comprises a phosphomolybdate of the formula [PMo 12 O 40 ] −3 . 
     
     
       10. The solution of  claim 5 , wherein said additional corrosion inhibiting additive comprises at least one transition metal compound which is different from said at least one zinc halide and from said heteropoly complex anion of a transition metal element. 
     
     
       11. The solution of  claim 10 , wherein said additional corrosion inhibiting additive comprises a transition metal which is different from the transition metal of the heteropoly complex anion. 
     
     
       12. The solution of  claim 10 , wherein said additional corrosion inhibiting additive is selected from the group consisting of nitrates, halides, and oxides of transition metal elements, and mixtures thereof. 
     
     
       13. The solution of  claim 12 , wherein said transition metal elements are selected from the group consisting of cobalt, nickel, tungsten, zirconium, manganese, chromium, and mixtures thereof. 
     
     
       14. The solution of  claim 5 , wherein said additional corrosion inhibiting additive comprises at least one compound of the metallic elements of Groups IIa to VIa of the Periodic Table of Elements. 
     
     
       15. The solution of  claim 14 , wherein said additional corrosion inhibiting additive is selected from the group consisting of oxides, sulfides, halides, nitrates, and mixtures thereof of metallic elements of Group IIIa to VIa. 
     
     
       16. The solution of  claim 15 , wherein said additional corrosion inhibiting additive is a halide of a metallic element of Groups IIIa to VIa. 
     
     
       17. The solution of  claim 16 , wherein said halide is selected from the group consisting of antimony bromide, germanium bromide, arsenic bromide, bismuth bromide, and mixtures thereof. 
     
     
       18. The solution of  claim 14 , wherein said additional corrosion inhibiting additive comprises antimony as the metallic element of Groups IIIa to VIa. 
     
     
       19. The solution of  claim 1 , wherein said solution comprises said at least one zinc halide, said at least one alkaline earth metal salt or mixture thereof in an amount from about 1 to about 80 weight percent, based on the total weight of the solution. 
     
     
       20. The solution of  claim 19 , wherein said solution comprises said at least one zinc halide, said at least one alkaline earth metal salt or mixture thereof in an amount from about 20 to about 60 weight percent, based on the total weight of the solution. 
     
     
       21. A solution having corrosion inhibiting properties useful in oil and gas well drilling systems, the solution comprising: 
       at least one salt selected from the group consisting of first transition metal salts, alkaline earth metal salts, and mixtures thereof;  
       at least one heteropoly complex anion of a transition metal element; and  
       at least one additional corrosion inhibiting agent selected from the group consisting of transition metal salts which are different from said first transition metal salts, salts of the metallic elements of Groups IIIa to VIa of the Periodic Table of Elements, and mixtures thereof, said heteropoly complex anion and said additional additive present in an amount sufficient to provide a corrosion inhibiting effect.  
     
     
       22. The solution of  claim 21 , wherein said first transition metal salt comprises one or more zinc halides. 
     
     
       23. The solution of  claim 21 , wherein said alkaline earth metal salt comprises one or more calcium halides. 
     
     
       24. The solution of  claim 21 , wherein said solution comprises at least one zinc halide and at least one calcium halide. 
     
     
       25. The solution of  claim 24 , wherein said solution comprises zinc bromide, optionally zinc chloride, calcium bromide, and optionally calcium chloride. 
     
     
       26. The solution of  claim 21 , wherein said heteropoly complex anion comprises a phosphomolybdate, and said additional additive comprises at least one transition metal salt. 
     
     
       27. The solution of  claim 26 , wherein said additional additive comprises at least one halide of cobalt, nickel, tungsten, zirconium, manganese, chromium, and mixtures thereof. 
     
     
       28. The solution of  claim 21 , wherein said heteropoly complex anion comprises a phosphomolybdate and said additional additive comprises at least one salt of a metallic element of Group IIIa to VIa. 
     
     
       29. The solution of  claim 28 , wherein said additional additive comprises a halide of the metallic elements of Group Va of the Periodic Table of Elements. 
     
     
       30. The solution of  claim 29 , wherein said additional additive comprises a compound selected from the group consisting of antimony bromide (SbBr 3 ), arsenic bromide, bismuth bromide and mixtures thereof. 
     
     
       31. The solution of  claim 21 , wherein said heteropoly complex anion is [PMo 12 O 40 ] −3 . 
     
     
       32. The solution of  claim 21 , wherein said first transition metal salts, alkaline earth metal salts, and mixtures thereof are present in an amount from about 20 to about 60 weight percent, based on the total weight of the solution. 
     
     
       33. An aqueous completion fluid for oil and gas well drilling systems having corrosion inhibiting properties, comprising at least one zinc halide, at least one calcium halide, or a mixture thereof; at least one phosphomolybdate; and at least one halide of the metallic elements of Group Va of the Periodic Table of Elements, said phosphomolybdate and said Group Va halide present in an amount sufficient to provide a corrosion inhibiting effect. 
     
     
       34. The aqueous completion fluid of  claim 33 , wherein said phosphomolybdate is [PMo 12 O 40 ] −3 , and said Group Va halide is antimony bromide (SbBr 3 ). 
     
     
       35. The aqueous completion fluid of  claim 34 , wherein said solution comprises zinc bromide, optionally zinc chloride, calcium bromide, and optionally calcium chloride.